Camilla Tøndel

Agalsidase Benefits Renal Histology in Young Patients with Fabry Disease

The effect of early-onset enzyme replacement therapy on renal morphologic features in Fabry disease is largely unknown. Here, we evaluated the effect of 5 years of treatment with agalsidase alfa or agalsidase beta in 12 consecutive patients age 7-33 years (median age, 16.5 years). We performed renal biopsies at baseline and after 5 years of enzyme replacement therapy; 7 patients had additional biopsies after 1 and 3 years. After a median of 65 months, biopsy findings from all patients showed total clearance of glomerular endothelial and mesangial cell inclusions, and findings from 2 patients showed complete clearance of inclusions from epithelial cells of the distal tubule. The 4 patients who received the highest dose of agalsidase exhibited substantial clearance of podocyte inclusions, and the youngest patient had nearly complete clearance of these inclusions. Linear regression analysis showed a highly significant correlation between podocyte globotriaocylceramide clearance and cumulative agalsidase dose (r=0.804; P=0.002). Microalbuminuria normalized in five patients. In summary, long-term enzyme replacement therapy in young patients can result in complete globotriaocylceramide clearance of mesangial and glomerular endothelial cells across all dosage regimens, and clearance of podocyte inclusions is dose-dependent.

Renal Biopsy Findings in Children and Adolescents With Fabry Disease and Minimal Albuminuria

BACKGROUND Information concerning renal pathological characteristics in Fabry disease in childhood is limited. Our objective is to define renal morphological abnormalities in children and adolescents with Fabry disease and minimal proteinuria. STUDY DESIGN Case series. SETTING & PARTICIPANTS 9 symptomatic patients (7 males, 2 females; age range, 7 to 18 years); 2 patients had received enzyme replacement therapy for 2 years. OUTCOMES & MEASUREMENTS Renal morphological changes assessed by using light and electron microscopy. RESULTS All patients had acroparesthesia and typical eye changes, 7 showed hypohidrosis, 7 had gastrointestinal problems, and 2 had typical angiokeratomas. Mean albumin-creatinine ratio was 38 mg/g [corrected] (range, 5.3 to 104.3 mg/g). [corrected] Measured glomerular filtration rate was normal in all patients. Light microscopy showed changes in glomerular, tubulointerstitial, or vascular compartments alone or in combination in 7 patients. Electron microscopy showed lesions in all patients. LIMITATIONS Small sample size. CONCLUSIONS Glomerular and vascular changes are present before progression to overt proteinuria and decreased glomerular filtration rate. The combination of acroparesthesia and mild albuminuria, glomerular endothelial cell deposits, and arteriopathy may constitute a clinical and morphological combination heralding a potentially progressive renal disease.

Safety and Complications of Percutaneous Kidney Biopsies in 715 Children and 8573 Adults in Norway 1988–2010

BACKGROUND AND OBJECTIVES Skepticism about performing renal biopsies is often because of uncertainty regarding risk of complications. The aim of this study was to evaluate safety and relevant complications of renal biopsies in pediatric and adult patients in a large national registry study. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Kidney biopsies reported in the Norwegian Kidney Biopsy Registry from 1988 to 2010 were included. Risk factors for major complications (blood transfusion and/or surgical or catheter intervention) were analyzed using logistic regression statistics. RESULTS Of the 9288 biopsies included, 715 were from children, and 8573 were from adults (≥18 years). Median age was 49 years (range=2 weeks to 94 years). Gross hematuria appeared after biopsy in 1.9% of the patients; 0.9% of patients needed blood transfusion, and 0.2% of patients needed surgical intervention/catheterization. The frequencies were 1.9%, 0.9%, and 0.2% in adults and 1.7%, 0.1% and 0.1% in children, respectively; 97.9% of the biopsies were without complications. In unadjusted analyses, risk factors for major complications were age>60 years, estimated GFR<60 ml/min per 1.73 m(2), systolic hypertension, acute renal failure, and smaller clinical center size (<30 biopsies/yr). Adjusted analyses (adjusted for age and/or estimated GFR) showed higher odds ratios (OR) only for smaller clinical center (OR=1.60 [1.02-2.50]) and low estimated GFR (estimated GFR=30-59 ml/min per 1.73 m(2) [OR=4.90 (1.60-14.00)] and estimated GFR<30 ml/min per 1.73 m(2) [OR 15.50 (5.60-43.00)]). CONCLUSIONS Percutaneous renal biopsy is a low-risk procedure in all ages. Reduced estimated GFR and smaller center size are associated with an increased risk of major complications.

Progressive podocyte injury and globotriaosylceramide (GL-3) accumulation in young patients with Fabry disease

Progressive renal failure often complicates Fabry disease, the pathogenesis of which is not well understood. To further explore this we applied unbiased stereological quantitative methods to electron microscopic changes of Fabry nephropathy and the relationship between parameters of glomerular structure and renal function in 14 young Fabry patients (median age 12 years). Renal biopsies were obtained shortly before enzyme replacement therapy from these patients and from nine normal living kidney donors as controls. Podocyte globotriaosylceramide (GL-3) inclusion volume density increased progressively with age; however, there were no significant relationships between age and endothelial or mesangial inclusion volume densities. Foot process width, greater in male Fabry patients, also progressively increased with age compared with the controls, and correlated directly with proteinuria. In comparison to the biopsies of the controls, endothelial fenestration was reduced in Fabry patients. Thus, our study found relationships between quantitative parameters of glomerular structure in Fabry nephropathy and age, as well as urinary protein excretion. Hence, podocyte injury may play a pivotal role in the development and progression of Fabry nephropathy.

Foot Process Effacement Is an Early Marker of Nephropathy in Young Classic Fabry Patients without Albuminuria

In Fabry disease, globotriaocylceramid (GL3) starts to accumulate in kidney cells in utero, and continues to accumulate throughout childhood and adulthood with progressive tissue damage, which may lead to renal failure. Material and Methods: Eight children with classical Fabry disease, median age 12 (range 4-16 years) had a renal biopsy performed before the initiation of enzyme replacement therapy (ERT). All patients were normalbuminuric and had normal GFR. Three patients were re-biopsied after three or five years. Results: In all patients, significant GL3-accumulation was found in several types of kidney cells with high amounts of GL3 in the podocytes. Segmental podocyte foot process effacement was shown in all but two patients; no effacement was seen neither in the youngest male patient at 4 years of age nor in a male aged 12. A 12-year-old female patient had normal podocyte foot processes before the start of ERT, but de novo foot process flattening and unchanged high score of podocyte GL3 accumulation were seen in the re-biopsy after three years of ERT (agalsidase alpha 0.2 mg/kg/every other week). Two boys showed worsening of podocyte effacement in kidney biopsy after five years of agalsidase alpha 0.2 mg/kg/eow. Conclusions: Podocyte foot process effacement was found in the majority of eight young classical Fabry patients of both genders after the age of 11 years, without clinical signs of Fabry nephropathy. Kidney biopsies are essential in the early diagnosis of nephropathy and in the evaluation of the response to enzyme replacement therapy of early Fabry nephropathy.

Longevity of B-Cell and T-Cell Responses After Live Attenuated Influenza Vaccination in Children

Background. The live attenuated influenza vaccine (LAIV) is the preferred vaccine for children, but the mechanisms behind protective immune responses are unclear, and the duration of immunity remains to be elucidated. This study reports on the longevity of B-cell and T-cell responses elicited by the LAIV. Methods. Thirty-eight children (3–17 years old) were administered seasonal LAIV. Blood samples were collected before vaccination with sequential sampling up to 1 year after vaccination. Humoral responses were evaluated by a hemagglutination inhibition assay, and memory B-cell responses were evaluated by an enzyme-linked immunosorbent spot assay (ELISpot). T-cell responses were evaluated by interferon γ (IFN-γ) ELISpot analysis, and intracellular cytokine staining of CD4+ T cells for detection of IFN-γ, interleukin 2, and tumor necrosis factor α was performed using flow cytometry. Results. LAIV induced significant increases in B-cell and T-cell responses, which were sustained at least 1 year after vaccination. Strain variations were observed, in which the B strain elicited stronger responses. IFN-γ–expressing T cell counts increased significantly, and remained higher than prevaccination levels 1 year later. Expression of T-helper type 1 intracellular cytokines (interleukin 2, IFN-γ, and tumor necrosis factor α) increased after 1 dose and were boosted after the second dose. Hemagglutination inhibition titers were sustained for 1 year. Vaccine-induced memory B cell counts were significantly increased, and the response persisted for one year. Conclusions. LAIV elicited B-cell and T-cell responses that persisted for at least 1 year in children. This is a novel finding that will aid future vaccine policy.

Characterization of Early Disease Status in Treatment-Naive Male Paediatric Patients with Fabry Disease Enrolled in a Randomized Clinical Trial

Trial Design This analysis characterizes the degree of early organ involvement in a cohort of oligo-symptomatic untreated young patients with Fabry disease enrolled in an ongoing randomized, open-label, parallel-group, phase 3B clinical trial. Methods Males aged 5–18 years with complete α-galactosidase A deficiency, without symptoms of major organ damage, were enrolled in a phase 3B trial evaluating two doses of agalsidase beta. Baseline disease characteristics of 31 eligible patients (median age 12 years) were studied, including cellular globotriaosylceramide (GL-3) accumulation in skin (n = 31) and kidney biopsy (n = 6; median age 15 years; range 13–17 years), renal function, and glycolipid levels (plasma, urine). Results Plasma and urinary GL-3 levels were abnormal in 25 of 30 and 31 of 31 patients, respectively. Plasma lyso-GL-3 was elevated in all patients. GL-3 accumulation was documented in superficial skin capillary endothelial cells (23/31 patients) and deep vessel endothelial cells (23/29 patients). The mean glomerular filtration rate (GFR), measured by plasma disappearance of iohexol, was 118.1 mL/min/1.73 m2 (range 90.4–161.0 mL/min/1.73 m2) and the median urinary albumin/creatinine ratio was 10 mg/g (range 4.0–27.0 mg/g). On electron microscopy, renal biopsy revealed GL-3 accumulation in all glomerular cell types (podocytes and parietal, endothelial, and mesangial cells), as well as in peritubular capillary and non-capillary endothelial, interstitial, vascular smooth muscle, and distal tubules/collecting duct cells. Lesions indicative of early Fabry arteriopathy and segmental effacement of podocyte foot processes were found in all 6 patients. Conclusions These data reveal that in this small cohort of children with Fabry disease, histological evidence of GL-3 accumulation, and cellular and vascular injury are present in renal tissues at very early stages of the disease, and are noted before onset of microalbuminuria and development of clinically significant renal events (e.g. reduced GFR). These data give additional support to the consideration of early initiation of enzyme replacement therapy, potentially improving long-term outcome. Trial Registration ClinicalTrials.gov NCT00701415

Uncertain diagnosis of fabry disease in patients with neuropathic pain, angiokeratoma or cornea verticillata: consensus on the approach to diagnosis and follow-up.

INTRODUCTION Individuals with neuropathic pain, angiokeratoma (AK) and/or cornea verticillata (CV) may be tested for Fabry disease (FD). Classical FD is characterised by a specific pattern of these features. When a patient presents with a non-specific pattern, the pathogenicity of a variant in the α-galactosidase A (GLA) gene may be unclear. This uncertainty often leads to considerable distress and inappropriate counselling and treatment. We developed a clinical approach for these individuals with an uncertain diagnosis of FD. MATERIALS AND METHODS A document was presented to an FD expert panel with background information based on clinical experience and the literature, followed by an online survey and a written recommendation. RESULTS The 13 experts agreed that the recommendation is intended for individuals with neuropathic pain, AK and/or CV only, i.e. without kidney, heart or brain disease, with an uncertain diagnosis of FD. Only in the presence of FD-specific neuropathic pain (small fibre neuropathy with FD-specific pattern), AK (FD-specific localisations) or CV (without CV inducing medication), FD is confirmed. When these features have a non-specific pattern, there is insufficient evidence for FD. If no alternative diagnosis is found, follow-up is recommended. CONCLUSIONS In individuals with an uncertain diagnosis of FD, the presence of an FD-specific pattern of CV, AK or neuropathic pain is sufficient to confirm the diagnosis of FD. When these features are non-specific, a definite diagnosis cannot (yet) be established and follow-up is indicated. ERT should be considered only in those patients with a confirmed diagnosis of FD.

Screening, diagnosis, and management of patients with Fabry disease: conclusions from a “Kidney Disease: Improving Global Outcomes” (KDIGO) Controversies Conference

Patients with Fabry disease (FD) are at a high risk for developing chronic kidney disease and cardiovascular disease. The availability of specific but costly therapy has elevated the profile of this rare condition. This KDIGO conference addressed controversial areas in the diagnosis, screening, and management of FD, and included enzyme replacement therapy and nonspecific standard-of-care therapy for the various manifestations of FD. Despite marked advances in patient care and improved overall outlook, there is a need to better understand the pathogenesis of this glycosphingolipidosis and to determine the appropriate age to initiate therapy in all types of patients. The need to develop more effective specific therapies was also emphasized.

Reaccumulation of globotriaosylceramide in podocytes after agalsidase dose reduction in young Fabry patients

Background Agalsidase-α 0.2 mg/kg every other week (eow) and agalsidase-β 1.0 mg/kg/eow are licensed in Europe as equipotent treatment of the α-galactosidase deficiency in Fabry disease. This case series describes the effects of agalsidase dose adjustments in serial kidney biopsies in switch patients. Methods All treatment-naïve patients with classical Fabry disease in our centre started on agalsidase-β 1.0 mg/kg/eow and subsequently switched to agalsidase-α 0.2 mg/kg/eow were included ( n = 3). The median age at enzyme replacement therapy start was 11 (range 7-18) years. Kidney biopsies were performed at baseline, after 5 years of agalsidase-β 1.0 mg/kg/eow and after 3 subsequent years of agalsidase-α 0.2 mg/kg/eow. One patient was re-biopsied 2 years after reswitch to agalsidase-β 1.0 mg/kg/eow. The scoring system of the International Scoring Group of Fabry Nephropathy was used. Results The patients completely cleared globotriaosylceramide (GL3) from mesangial and endothelial cells and partly cleared podocytes on agalsidase-β 1.0 mg/kg/eow. Reaccumulation of GL3 in podocytes, but not in the mesangium or endothelium, occurred after 3 years of agalsidase-α 0.2 mg/kg/eow. Subsequent reduction of podocyte GL3 was observed in the single patient rebiopsied 2 years after reswitch to agalsidase-β 1.0 mg/kg/eow. Conclusion Partial clearance, reaccumulation and renewed partial clearance of podocyte GL3 deposits in serial kidney biopsies over 8-10 years were seen in parallel with agalsidase dose adjustments. Repeated kidney biopsies may impact therapeutic choices in Fabry disease.